Criteria for the accurate interpretation of changes in left ventricular ejection fraction and cardiac volumes as assessed by rest and exercise gated radionuclide angiography

Although serial left ventricular ejection fraction and volumetric measurements using gated radionuclide angiography are commonly used to evaluate clinical changes and therapeutic outcomes in individual patients, criteria are not available for accurately interpreting whether a change in any of these hemodynamic measurements is clinically meaningful. Accordingly, the magnitude of inherent variability among sequential measurements of hemodynamic variables assessed by gated radionuclide angiography was investigated in a double-blind placebo-controlled fashion in 39 patients during two placebo periods separated by 6 weeks. All patients analyzed had remained clinically stable during the study period. Although the mean values for all hemodynamic variables between the two placebo periods were minimally changed, the differences in individual patients were striking. Criteria were developed to allow meaningful interpretation of changes in hemodynamic variables by estimating the likelihood that an observed change is due to variability alone. On the basis of this analysis of placebo radionuclide angiographic data, variation due to chance alone is unlikely to account for all variability if a change observed between the two rest gated studies in a patient is greater than or equal to 7% units for left ventricular ejection fraction, greater than or equal to 45 ml/m2 for end-diastolic volume index, greater than or equal to 35 ml/m2 for end-systolic volume index, greater than or equal to 20 ml/m2 for stroke volume index and greater than or equal to 1.25 liters/min per m2 for cardiac index. An observed 4% unit change in left ventricular ejection fraction (increase or decrease) after a medical intervention in an individual patient occurs by random variation greater than 25% of the time.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of fiber optical and video monitor stimulators in normals and multiple sclerosis patients

A comparison of VEP findings using a fiber optical stimulator with three color combinations (black/red, black/green and red/green) and a conventional video monitor stimulator in black/white was performed in 3 groups of subjects: a group with definite lesions in the visual pathway, a group with suspected lesions and a control group. No significant correlations of P100 latency were found in the normative group, probably because of the small range of their values. All correlations were significant in the two patient groups, except for the red/green stimuli in the definite group. In general, the red/green combination was inferior to other color combinations in eliciting VEPs. The patient groups with definite, as well as suspected, lesions indicated no benefit from the color stimuli, as compared with black/white. The major advantage of the fiber optical stimulator is its simplicity, the lack of stimulus artifacts and the accessibility to the patient's bed side, thanks to its small size. Stimulators with higher illuminance and improved pattern element shape should narrow the still unacceptable normative variability of the wave forms recorded.     

Thyroid function tests in acutely ill patients. Comparison of analogue based free thyroid hormone assays with free thyroxine index

A prospective study of 100 acutely ill patients was carried out to assess the value of the free thyroxine (FT4) assay as a replacement screening procedure for the free thyroxine index (FTI). We found that the FT4 assay was significantly influenced by the albumin concentration, so that the number of follow-up tests required increased markedly. This was especially true at the low end of the FT4 range where the need for thyrotropin assays increased by 162%. The free triiodothyronine (FT3) assay was also shown to be albumin dependent. It is not useful to replace one set of difficulties due to protein binding with another, and overall it was concluded that it is not cost-effective to screen hospital patients for thyroid dysfunction using free hormone assays based on labelled analogue techniques.     

Histamine and endotoxin contamination of hay and respirable hay dust

Three distinct samples collected from a barn in which an outbreak of respiratory problems occurred were examined for possible etiologic agents. No causal relationship could be established from the results of this study; however histamine concentrations as high as 0.5 ng/mg for bulk hay (in the absence of measurable creatinine levels) along with 6138.3 endotoxin units/mg of hay were present in the samples. Both endotoxin and histamine could be recovered from respirable hay dust. The authenticity of the histamine found in the hay was evaluated with high-performance liquid chromatography and radioimmunoassay. Histamine release caused by hay extracts was evaluated with the use of leukocytes from the farmer and a referent. Histamine is known to modulate the immune system, but the role of occupational or environmental exposure to histamine in respiratory disease is unknown.     

Auditory brainstem evoked potentials in evaluating the efficacy of surgical ventilation of the middle ear

Conductive hearing loss in children is most commonly associated with Secretory otitis media (S.O.M.). Since auditory brainstem evoked potentials (ABEP) reflect conductive damage in prolonged peak latencies, the present study evaluated the efficacy of surgery for ventilating the middle ear, by comparing changes in peak latencies. These changes were compared in 4 groups of children (4-12 years old): children with S.O.M. in the past, who recovered as a result of conservative treatment; children with S.O.M. in the past, who had been operated on with insertion of ventilation tubes (V.T.); children with S.O.M. in the past, who had been operated on and who still had V.T. at the time of study, and a control group with healthy ears. In all, 183 ears were tested. The results indicate that there is no significant audiometric and electrophysiological difference between the groups who recovered with or without V.T.     

马缨丹叶的化学成分研究

自马缨丹(Lantana camara L.)叶中分离到六个化合物。经光谱(UV,IR,MS,¹HNMR,¹³CNMR)和化学分析,分别鉴定为齐墩果酮酸(oleanonic acid,Ⅰ),马缨丹甲素(lantadene A,Ⅱ),马缨丹乙素(lantadene B,Ⅲ),lantanilic acid(Ⅳ),icterogenin(Ⅴ)和4′,5-二羟基-3,7-二甲氧基黄酮-4′-O-β-D-吡喃葡萄糖甙(4′,5-dihydroxy-3,7-dimethoxyflavone-4′-O-β-D-glucopyranoside,Ⅵ)。Ⅵ是新化合物,命名为马缨丹黄酮甙(camaroside)。     

N omega-nitro-L-arginine attenuates the accumulation of aortic cyclic GMP and the hypotension produced by zaprinast.

To determine if N omega-nitro-L-arginine (NNA), an inhibitor of the synthesis and/or release of endothelium-derived relaxing factor (EDRF), alters the response to zaprinast, a selective inhibitor of cyclic GMP (cGMP) phosphodiesterase, zaprinast (3-30 mg/kg) or vehicle (1 ml/kg) was given to conscious, spontaneously hypertensive rats (SHR) in a cumulative i.v. dose-response manner 30 min after pretreatment with NNA (1 or 3 mg/kg) or saline (1 ml/kg). Mean arterial pressure (MAP) was measured 5 min after each dose of zaprinast. Five minutes after the last dose of zaprinast (30 mg/kg), the rats were anesthetized with pentobarbital (25 mg i.v.). A segment of the abdominal aorta was freeze-clamped in situ and removed for the determination of cGMP levels. NNA (3 mg/kg) decreased basal aortic cGMP levels by 54% and increased MAP by 37 +/- 2 mm Hg. Zaprinast (30 mg/kg) increased aortic cGMP by 187% and decreased MAP by 49 +/- 4 mm Hg. NNA (3 mg/kg) reduced the accumulation of cGMP in aortic tissue (from 4.1 +/- 0.4 to 1.3 +/- 0.1 fmol/microgram protein) and attenuated the depressor response (from -49 +/- 4 to -31 +/- 4 mm Hg) produced by zaprinast. These data are consistent with the hypothesis that NNA inhibits the tonic release of EDRF and that the depressor effects of zaprinast are due, at least in part, to the potentiation of the vasodilator effects of EDRF in vivo. Moreover, since the changes in MAP produced by NNA and zaprinast were significantly correlated with cGMP levels in aortic tissue, the concentration of cGMP in vascular tissue may be a determinant of blood pressure in SHR.     

Nuclear Freeze and Disarmament: A Mandate for Community Health Nursing

Nuclear war is presented as the “ultimate epidemic,” and requires the involvement of community health nurses in preventing it. The health consequences of nuclear war as well as present costs to human health of the current arms race are enormous. Nursing actions and primary prevention are discussed.